Optical readers, such as hand-held bar code readers, are conventionally used to read and interpret bar code data printed on articles offered for sale, items subject to inventory, and many other media. Typically, a bar code comprises a series of encoded symbols, and each symbol consists of a series of light and dark regions, typically in the form of rectangles. The widths of the dark regions, the bars, and/or the widths of the light spaces between the bars indicate the encoded information. A bar code reader illuminates the code and senses light reflected from the code to detect the widths and spacings of the code symbols and derive the encoded data.
Bar code reading type data input systems improve the efficiency and accuracy of data input for a wide variety of applications. The ease of data input in such systems facilitates more frequent and detailed data input, for example to provide efficient inventories, tracking of work in progress, etc. To achieve these advantages, however, users or employees must be willing to consistently use the bar code readers. The readers therefore must be easy and convenient to operate and readily connectable to an associated host system and/or external power source.
A variety of scanning devices are known. One particularly advantageous type of reader is an optical scanner which scans a beam of light, such as a laser beam, across the symbols. Laser scanner systems and components of the type exemplified by U. S. Pat. Nos. 4,251,798; 4,360,798; 4,369,361; 4,387,297; 4,593,186; 4,496,831; 4,409,470; 4,460,120; 4,607,156; 4,673,803; 4,736,095; 4,758,717; 4,816,660; 4,808,804; 4,816,661; 4,760,248; 4,871,904; 4,806,742; and 4,845,350, as well as U.S. application Ser. Nos. 07/148,669 and 07/147,708-- all of these patents and patent applications being owned by the assignee of the instant invention and being incorporated by reference herein--have generally been designed to read indicia having parts of different light reflectivity, e.g., bar code symbols, particularly of the Universal Product Code (UPC) type, at a certain working or reading distance from a hand-held or stationary scanner.
In a typical optical scanner system, a light source such as a laser generates a light beam which is optically modified to form a beam spot of a certain size at the working distance and is directed by optical components along a light path toward a bar code symbol located in the vicinity of the working distance for reflection from the symbol. An optical sensor or photodetector having a field of view extending across and slightly past the symbol detects light of variable intensity reflected off the symbol and generates electrical signals indicative of the detected light. A scanning component is situated in the light path. The scanning component may either sweep the beam spot across the symbol and trace a scan line across and past the symbol, or scan the field of view of the photodetector, or do both.
A digitizer, of an associated host system or included in the scanner, processes the analog signal to produce a pulse signal where the widths and spacings between the pulses correspond to the widths of the bars and the spacings between the bars. The digitizer serves as an edge detector or wave shaper circuit, and the threshold value set by the digitizer determines what points of the analog signal represent bar edges. The pulse signal from the digitizer is applied to a decoder. The decoder first determines the pulse widths and spacings of the signal from the digitizer. The decoder then analyzes the widths and spacings to find and decode a legitimate bar code message. This includes analysis to recognize legitimate characters and sequences, as defined by the appropriate code standard, and may include an initial recognition of the particular standard the scanned symbol conforms to. Recognition of the standard is referred to as autodiscrimination. Typically, the various decoder functions are performed by a microprocessor, with associated program memory and random access data memory.
FIG. 10 illustrates an example of a prior art bar code reader unit 100 implemented as a gun shaped device, having a pistol-grip type of handle 153. A lightweight plastic housing 155 contains laser light source 146, detector 158, optics and signal processing circuitry and CPU 140. The bar code reader is connected to an associated host system and/or receives power through cable 180. Cable 180 is permanently secured at an end of handle 153 by strain relief member 182. Wires 184 of cable 180 are internally attached to circuit board 161.
A light-transmissive window 156 in the front end of the housing 155 allows the outgoing light beam 151 to exit and the incoming reflected light 152 to enter. The reader 100 is designed to be aimed at a bar code symbol 170 by the user from a position in which the reader 100 is spaced from the symbol, i.e., not touching the symbol or moving across the symbol.
As further depicted in FIG. 10, a suitable lens 157 (or multiple lens system) may be used to focus the scanned beam into a scanning spot at an appropriate reference plane. A light source 146, such as a semiconductor laser diode, introduces a light beam into the axis of the lens 157, and the beam passes through a partially-silvered mirror 147 and other lenses or beam-shaping structure as needed. The beam is reflected from an oscillating mirror 159 which is coupled to a scanning motor 160 energized when the trigger 154 is pulled. The oscillation of the mirror 159 causes the reflected beam 151 to scan back and forth in a desired pattern.
A variety of mirror and motor configurations can be used to move the beam in a desired scanning pattern. For example, U.S. Pat. No. 4,251,798 discloses a rotating polygon having a planar mirror at each side, each mirror tracing a scan line across the symbol. U.S. Pat. Nos. 4,387,297 and 4,409,470 both employ a planar mirror which is repetitively and reciprocally driven in alternate circumferential directions about a drive shaft on which the mirror is mounted. U.S. Pat. No. 4,816,660 discloses a multi-mirror construction composed of a generally concave mirror portion and a generally planar mirror portion. The multi-mirror construction is repetitively reciprocally driven in alternate circumferential directions about a drive shaft on which the multi-mirror construction is mounted.
The light 152 reflected back by the symbol 170 passes back through the window 156 for application to the detector 158. In the exemplary reader 100 shown in FIG. 10, the reflected light reflects off of mirror 159 and partially-silvered mirror 147 and impacts on the light sensitive detector 158. The detector 158 produces an analog signal proportional to the intensity of the reflected light 152. This signal is processed and digitized by circuitry mounted on circuit board 161 and decoded by microprocessor 140.
To scan a symbol 170, a user aims the bar code reader unit 100 and operates movable trigger switch 154 to activate the light beam 151, the scanning motor 160 and the detector circuitry. If the scanning beam is visible, the operator can see the scan pattern on the surface on which the symbol appears and adjust aiming of the reader 100 accordingly. If the light produced by the source 146 is marginally visible, an aiming light may be included in the optical system. The aiming light if needed, produces a visible-light spot which may be fixed, or scanned just like the laser beam; the user employs this visible light to aim the reader unit at the symbol before pulling the trigger.
The reader 100 may also function as a portable computer terminal. If so, the bar code reader 100 would include a keyboard 148 and a display 149, such as described in the previously noted U.S. Pat. No. 4,409,470.
FIG. 11 is a diagram showing a reader 100 connected to host data equipment. Reader 100 includes a generally gun-shaped housing having a handle 153 of generally rectangular cross-section and generally elongated along a handle axis. A generally horizontally-elongated barrel portion 163 includes the optical scanning components for generating and directing a laser beam onto a target and detecting laser light reflected therefrom. The body and handle are constituted of lightweight, resilient, shock-resistant, self-supporting material, such as a synthetic plastic material. The plastic housing preferably is injection molded, but can be vacuum-formed or blow-molded to form a thin, hollow shell encasing the optical and electronic components supplying the output signals indicative of the detected light. These signals are provided by cable 180 to a decode module 101. Decode module 101 converts the signals representing the bar code into corresponding numeric data in either binary, binary-coded-decimal, or ASCII format which is supplied to host device 103 for further processing.
In optical scanners of the type discussed above, the scanner is attached to a host system and/or receives power through a permanently attached cable. While the cable may be attached by a removable multi-pin electrical connector to permit replacement or changing of the scanner device, conventional multi-pin electrical connectors are difficult to properly align and are prone to damage when handled by inexperienced personnel. Further, these connectors do not provide an environmentally sealed interface to prevent introduction of contaminants including dirt and dust into the scanner.
Some conventional multi-pin connectors include metallic screw rings for securely attaching the connector body to an electronic device. These structures can also provide some environmental protection of the electrical connectors and prevent the introduction of dust and dirt into the scanner. However, these connectors can be difficult to use and are easily damaged. Further, the metallic connectors must be manually assembled and are not readily adaptable to automated assembly techniques used for other multi-pin types of connectors.
Alternatively, plastic multi-pin connectors are used to connect equipment. However, plastic connectors are not durable, are easily dislodged, and do not provide adequate environmental protection.
From the above discussion of the state of the art, it becomes clear that a need exists for a connector assembly for attaching and securing a signal cable to a scan unit, the connector assembly being adaptable to automated assembly techniques, resistant to operator abuse and mishandling, and readily adaptable to a broad range of connector types including multi-pin electrical, fiber optic and coaxial signal cables.